Method for extracting corosolic acid from plant

The invention provides a method for extracting and preparing corosolic acid from plants, which comprises the steps of poaching and removing water-soluble substances, extracting basic organic solvents of total triterpene acids and enriching and purifying macroporous absorption resin of corosolic acid. Plants containing corosolic acid are adopted as raw material and the water-soluble substances are removed after boiled by pure water; regarding filter residue 30 to 60 percent of basic ethanol or methanol water solution is adopted to extract total triterpene acids and go through settling separation under the condition that pH is 4.5 to 7.5 to obtain crude products of total triterpene acids which are fully dissolved by 85 to 100 percent of ethanol or methanol and undissolved substances are removed; filtered liquor goes through the absorption and elution of macroporous absorption resin; the final concentration of ethanol or methanol in the elution liquor of corosolic acid is adjusted to be less than or equal to 50 percent and pH value thereof is adjusted to be less than or equal to 7.0; corosolic acid is obtained through settling separation under the condition. The method has simple preparation technique, high separation and purification efficiency, easy industrial production, low production cost and relatively great generalization